Hollow fiber membranes are essential components of artificial lung systems. These hollow fiber mats are required for removing carbon dioxide or for adding oxygen to patient's blood via extracorporeal circulation. Hollow fibers are manufactured in various ways as seen in U.S. 2010/051180 A1, U.S. Pat. No. 4,226,378, and JP 8299763. The hollow fibers used to construct these mats are delicate. For example, the hollow fibers used in the Hemolung Cartridge of the Hemolung Respiratory Assist System are composed of polypropylene and are approximately 300 microns in diameter and with a 30 micron wall thickness. Hollow fibers can also be coated with coatings such as siloxane. Problems arise when guiding the hollow fiber into a knitting machine. A variety of tools have been traditionally utilized to guide fibers and yarns into knitting machines. These tools in many cases utilize ceramic wear surfaces which are extremely hard and have low coefficients of friction. Metal guides as well as combination ceramic/metal guides have been utilized to insert the hollow fiber into the knitting machine. For example, one type of guide is essentially a tube through which the coated hollow fiber passes. The tube is mounted to an arm which moves back and forth to lay the hollow fiber into position. Despite using ceramic contact surfaces, the tube guide damages the siloxane coating on the hollow fibers. Microscopic analysis shows that siloxane coating had been scrapped off. Also the severe sharp exit angle of the tube caused flattening of the hollow fiber. A guide that utilizes dynamic friction and that keeps the hollow fiber aligned without bending as it is being fed into a knitting machine is necessary.
One attempt to solve the problem of causing damage to the hollow fiber is seen in JP 2008-196066A which describes a guide utilizing dynamic rollers for a Russell knitting machine. A hollow fiber passes through a complex tension apparatus eventually looping over a horizontal roller in a fixed position that feeds the hollow fiber in between the vertical rollers. These vertical rollers are set in parallel, are spaced apart, and are always in a fixed position. The hollow fiber then passes through a pair of closely set rollers that feed into a Russel knitting machine. These rollers move horizontally in the knitting machine via a conveyor belt mechanism. In the extreme horizontal positions the vertical rollers maintain horizontal alignment, but this design does not provide for front to back alignment roller guides. It also has the disadvantage of not providing for a plurality of top entry angles and therefore is not very adaptable to other systems. Another disadvantage is that any alteration in hollow fiber feeding process requires manual readjustment. Other yarn guides for feeding knitting or spinning machines can be found in U.S. Pat. No. 6,182,475 B1, U.S. Pat. No. 6,016,650, JP 2004-204400, and JP 6093543, but none of these singularly resolve the above discussed issues.
There is a need for a delicate fiber guide that utilizes dynamic friction and that provides for the horizontal and the front to back positioning of the delicate fiber, keeping it vertically aligned as it is being fed, for example into a knitting machine. There is also a need for a guide that allows for the delicate fiber to be fed from plurality of overhead angles.